As a rule, two-dimensional positioning systems are realized as a T- or H-structure. In this case, a portal is moved in an X-direction by a motor or even two motors, and a slide arranged in a movable manner on the portal and carrying the tool is positioned in a Y-direction by a further motor. Relatively large masses are to be moved in the process. The accelerations achievable are comparatively low, so that the working speed of such a system is accordingly also relatively low.
During the automatic fitting of printed circuit boards with components, for example, the tool in the form of a fitting head has to be moved at high speed over the working area. Positioning systems of the aforesaid type can no longer meet the desires for higher production rates.
There is also the fact that, in addition to the two coordinate directions X and Y, a lifting movement of the tool in the direction of a third coordinate direction Z and a rotation about this axis by an angle φ may also be required. For this reason, these two functions have to be integrated via additional subassemblies. This further increases the moving masses and possibly impairs the working area, which in the T- or H-structure is in any case smaller than the construction area.